Water and sewer rates are set to rise again in 2013 for Gainesville Public Utilities customers after Gainesville City Council approved an increase Tuesday night. Water rates will see a 3 percent hike, and sewer rates will be 3.5 percent higher effective Jan. 1. The rate increases, which will require a final City Council vote later this month, are intended to account for rising costs in energy and water-treatment chemicals, said Mayor Danny Dunagan.